Mississippi Commission on Environmental Quality v. Environmental Protection Agency
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Full Opinion
The Congress enacted the Clean Air Act (the Act), 42 U.S.C. §§ 7401 et seq., “to protect and enhance the quality of the Nation’s air resources so as to promote the public health and welfare and the productive capacity of its population.” Id. § 7401(b)(1). At issue in this case is Title I of the Act, which requires the Environ
In these consolidated petitions, several states, counties, industrial entities and environmental organizations challenge the EPA’s determination that certain geographic areas are, or are not, in “attainment” with the EPA’s ground-level ozone NAAQS. Id. Some argue that the Act, as applied to them, violates various Constitutional provisions; others argue that the EPA misconstrued the terms of the Act. Virtually every petitioner argues that, for one reason or another, the EPA acted arbitrarily and capriciously in making its final NAAQS designations. But because the EPA complied with the Constitution, reasonably interpreted the Act’s critical terms and wholly satisfied — indeed, in most instances, surpassed — its obligation to engage in reasoned decision-making, we deny the consolidated petitions for review in their entirety.
I. BACKGROUND
The EPA began the odyssey resulting in these consolidated petitions nearly seven years ago. Along the way, it construed a variety of the Act’s provisions, promulgated regulations and issued informal guidance to assist in the collaborative area-designation effort between it and the states. Before discussing the substance of the issues, a brief ovei*view of the Act and the underlying proceedings in this case is in order.
A. The Clean Air Act
Under the Act, the EPA must promulgate NAAQS, which set the maximum ambient, or outdoor, air concentrations for six pollutants that “may reasonably be anticipated to endanger public health or welfare.” 42 U.S.C. § 7408(a)(1). Once it establishes a NAAQS, the EPA must designate each “area” in the United States as “attainment” or “nonattainment.” See id. § 7407(d)(1)(A)(i)-(ii). Alternatively, the EPA may designate an area as “unclassifiable” if the area “permit[s] no determination given existing data.” Catawba Cnty., N.C. v. EPA, 571 F.3d 20, 26 (D.C.Cir.2009) (citing 42 U.S.C. § 7407(d)(1)(A)(i)-(iii)). The EPA treats an “unclassifíable” area as if it were in attainment. See 42 U.S.C. § 7471.
Generally speaking, the EPA designates an area that meets the relevant NAAQS as in attainment, while areas that exceed the NAAQS receive a nonattainment designation. See Catawba Cnty., 571 F.3d at 26. But even if an area’s ambient air concentration complies with the relevant NAAQS, the EPA nonetheless designates it as non-attainment if it “contributes” to a NAAQS violation in a “nearby area.” See 42 U.S.C. § 7407(d)(1)(A)(i). The Act does not define the terms “contributes,” “nearby” or “area.”
The EPA works collaboratively with the states to determine the NAAQS-attainment status for all areas within a respective state’s borders. No later than one year after the EPA promulgates a new or revised NAAQS, each state must submit recommended “initial designations” to the EPA. Id. § 7407(d)(1)(A). A state’s initial designations must suggest both the appropriate geographic boundaries for each “area” and whether the EPA should classify the suggested area as attainment, non-attainment or unclassifíable. See id. § 7407(d)(l)(A)-(B).
While the EPA has ultimate authority to determine each area’s attainment status, each state has “primary responsibility” for ensuring that the geographic areas within its borders either maintain attainment or progress towards it. 42 U.S.C. § 7407(a). Accordingly, once the EPA finalizes its designations, each state must submit to the EPA a State Implementation Plan (SIP) specifying how the NAAQS “will be achieved and maintained.” Id. For areas in attainment, the SIP must simply “contain emission limitations and such other measures as may be necessary ... to prevent significant deterioration of air quality.” Id. § 7471.
For a nonattainment area, however, the Act imposes more stringent requirements. A SIP from a state with a nonattainment area must demonstrate that the state intends to implement “all reasonably available control measures” and “reasonably available control technology” to bring the area into attainment. Id. § 7502(c)(1). The Act also imposes deadlines, or “attainment dates,” on an offending area. See id. § 7502(a)(2)(A). For a violation of a primary
B. The 2008 Ozone NAAQS and the EPA’S 2008 Guidance
On March 12, 2008, the EPA promulgated new primary and secondary NAAQS for ambient ozone,
Both the EPA’s 2008 primary and secondary ozone NAAQS reduced the maximum allowable daily average eight-hour level of ozone from 0.08 parts per million (ppm) to 0.075 ppm. See National Ambient Air Quality Standards for Ozone, 73 Fed.Reg. 16,436, 16,436-37 (Mar. 27, 2008). By setting these new NAAQS, the EPA triggered the states’ responsibility to submit their initial designations. See 42 U.S.C. § 7407(d)(1)(A). To assist this process, the EPA issued a guidance titled “Area Designations for the 2008 Revised Ozone National Ambient Air Quality Standards” [hereinafter 2008 Guidance] on December 4, 2008, which included several matters relevant to the instant petitions.
First, the 2008 Guidance instructed states on the quality of data it expected them to consider. Specifically, it recommended that the states “identify violating areas using the most recent three consecutive years of quality-assured, certified air quality data.” 2008 Guidance at 2. The 2008 Guidance also informed the states that “[i]n general, [NAAQS] violations [will be] identified using data from ... monitors that are sited and operated in accordance with [EPA regulations located at] 40 C.F.R. Part 58.” Id.
Second, the 2008 Guidance provided instruction for establishing geographic boundaries around nonattainment areas, noting first that the “EPA believes it is important to examine ozone-contributing emissions across a relatively broad geographic area.” 2008 Guidance at 3. Accordingly, the 2008 Guidance recommended that if an air-quality monitor reports a NAAQS violation, the state should consider using the Core Based Statistical Area (CBSA) or Combined Statistical Area (CSA) in which the monitor is located as the “presumptive” boundary.
The 2008 Guidance made plain, however, that CSAs, CBSAs and county lines were merely presumptive boundaries, recognizing that “area-specific analyses ... may support nonattainment area boundaries that are larger or smaller than the presumptive area starting point.” Id. Stressing that “each potential nonattainment area should be evaluated on a case-by-case basis,” the 2008 Guidance instructed the states to consider nine factors when determining a nonattainment area’s borders. See id. at 2, Attach. 2. These include (1) air-quality data; (2) emissions data (such as location of emissions sources and contribution to ozone concentrations); (3) population density and degree of urbanization (including commercial development); (4) traffic and commuting patterns; (5) population growth rates and patterns; (6) meteorology (such as weather and air-transport patterns); (7) geography and topography (such as mountain ranges or other air-basin boundaries that could affect ozone dispersion); (8) jurisdictional boundaries (such as counties, air districts, existing nonattainment area boundaries and regional planning authority boundaries) and (9) the level of control of emissions sources. See id. Attach. 2. The 2008 Guidance stated that the EPA planned to consider these same factors, “along with any other relevant information,” in determining whether to modify the states’ initial designations. Id.
C. The 2008 Ozone Designation Process
By 2009, all states had submitted their initial designations to the EPA. Rather than immediately reviewing the initial designations, however, the EPA halted the designation process to consider whether to lower the ozone NAAQS even further. This delay prompted a lawsuit by Wild-Earth Guardians — an environmental-group petitioner in this case — that sought to compel the EPA to complete the stalled ozone NAAQS designation process.
The EPA notified the states in September 2011 that it intended to finalize the ozone NAAQS designations by the May 31, 2012 deadline set forth in the consent decree. In accordance with the 2008 Guidance’s instruction to “identify violating areas using the most recent three consecutive years of quality-assured, certified air quality data,” 2008 Guidance at 2, virtually every state had already submitted air-quality data from 2008 to 2010 by the time the EPA resumed the designation process. Although the EPA assured the states that it still planned to consider the recommended designations and ozone data they had submitted initially, it recognized that some states may have collected more recent air-quality data for their regions. For this reason, the EPA allowed the states to provide updated recommendations and analyses — so long as any updated air-quality data was certified for quality — but assured them that they were under no obligation to do so. In response to this invitation, several states updated their initial designations and some submitted air-quality data from 2009 to 2011 to replace their older 2008 to 2010 data. The states seeking to use data from 2009 to 2011 agreed to certify their data for
The EPA then reviewed each state’s initial designations to determine whether to modify them. It first examined the air-quality submissions from the states to determine which monitors reported ozone NAAQS violations. If a state certified its air-quality data from 2011 by the February 29, 2012 deadline, the EPA generally considered its air-quality data from the years 2009 to 2011. For all other states, the EPA considered air-quality data from 2008 to 2010.
After identifying NAAQS-violating monitors, the EPA decided whether to alter the states’ respective recommended nonattainment boundaries. To do so, the EPA used a multi-factor, weight-of-the-evidence test that tracked — but was not identical to — the nine-factor test in the 2008 Guidance. Specifically, the EPA collapsed the 2008 Guidance’s nine-factor test into a five-factor test, which examined (1) “Air Quality Data,” or whether an area’s monitor reported a NAAQS violation; (2) “Emissions Data,” including emissions levels and controls, population, population density, population growth, degree of urbanization and traffic and commuting patterns; (3) “Meteorology,” including wind speed and direction; (4) “Geography/Topography,” which examined the effect of physical land features on the distribution of ozone and (5) “Jurisdictional Boundaries,” which helped determine whether certain areas could effectively carry out air-quality planning and enforcement functions for nonattainment areas.
Once attainment designations were made, the EPA notified the states of any proposed modifications it deemed necessary and invited them to submit any additional data or comments they wished to have the EPA consider. Although not required by statute, see 42 U.S.C. § 7407(d)(2)(B), the EPA also opened a 30-day public comment period on the proposed notifications. Several states, organizations and members of the public — including many of the petitioners in this case— submitted comments. The EPA considered the comments and then promulgated its final designations, which identified 48 nonattainment areas in 26 states, the District of Columbia and Indian country. The nonattainment areas included 192 counties in toto and 36 counties in part. The EPA published the majority of its final designations on May 21, 2012, see 2008 Designations Rule, 77 Fed.Reg. at 30,088, and in the case of certain Chicago-area designations, on June 11, 2012, see Air Quality Designations for the 2008 Ozone National Ambient Air Quality Standards for Several Counties in Illinois, Indiana, and Wisconsin; Corrections to Inadvertent Errors in Prior Designations, 77 Fed.Reg. 34,221, 34,221 (June 11, 2012).
After the EPA received and denied 29 petitions for reconsideration, the parties in this consolidated case
II. COMMON LEGAL PRINCIPLES
Before addressing the petitioners’ individual challenges, we think it helpful to discuss several principles that bear on most, if not all, of the issues the petitioners have raised.
First, we review the EPA’s NAAQS designations under the same standard we use in reviewing a challenge brought under the Administrative Procedure Act (APA). See Allied Local & Reg’l Mfrs. Caucus v. EPA, 215 F.3d 61, 68 (D.C.Cir.2000). Accordingly, we will set aside a NAAQS designation by the EPA only if it is “arbitrary, capricious, an abuse of discretion, or otherwise not in accordance with law.” Catawba Cnty., 571 F.3d at 41 (quoting 5 U.S.C. § 706(2)(A)). We must, however, give an “extreme degree of deference” to the EPA’s evaluation of “scientific data within its technical expertise,” City of Waukesha v. EPA, 320 F.3d 228, 247 (D.C.Cir.2003), especially where, as here, we review the “EPA’s administration of the complicated provisions of the Clean Air Act.” Catawba Cnty,, 571 F.3d at 41 (citing Nat’l Ass’n of Clean Air Agencies v. EPA, 489 F.3d 1221, 1229 (D.C.Cir.2007)). Because the EPA’s “basic obligation” is to conduct “reasoned decisionmaking,” id. at 25, we will uphold its action if the record shows that the EPA “considered all relevant factors and articulated a ‘rational connection between the facts found and the choice made,’ ” id. at 41 (quoting Burlington Truck Lines, Inc. v. United States, 371 U.S. 156, 168, 83 S.Ct. 239, 9 L.Ed.2d 207 (1962)).
Second, we have long since rejected the argument that the EPA violates the Act if it uses a holistic, multi-factor, weight-of-the-evidence test for determining whether a given area contributes to a NAAQS violation. See ATK Launch Sys., Inc. v. EPA, 669 F.3d 330, 336-37 (D.C.Cir.2012) (challenge to 2006 fine particulate matter NAAQS designations); Catawba Cnty., 571 F.3d at 46 (challenge to 1997 fine particulate matter NAAQS designations). Indeed, in Catawba County, we made explicit that the EPA does not violate the Act even if it fails to adopt “a bright-line, ‘objective’ test” for determining contribution and we also held that the “EPA’s failure to quantify its analysis” does not render “its interpretation of ‘contribute’ arbitrary and capricious and therefore unreasonable.” 571 F.3d at 39. Rather, because “[a]n agency is free to adopt a totality-of-the-circumstances test to implement a statute that confers broad discretionary authority, even if that test lacks a definite ‘threshold’ or ‘clear line of demarcation to define an open-ended term,”’ we have held that, “[t]o be reasonable, such an ‘all-things-considered standard’ must simply define and explain the criteria the agency is applying.” Id.
With this background in mind, we now turn to the petitioners’ challenges.
III. THE PETITIONERS’ CHALLENGES
A. Delaware & Connecticut
We begin with a challenge to the EPA’s construction of the key statutory provision in this case. Petitioners Delaware and Connecticut challenge the EPA’s refusal to designate broad, multi-state non-attainment areas to address the issue of long-range ozone transport. According to the States, the EPA’s final designations are inconsistent with its statutory mandate to designate areas as nonattainment if they “contribute[ ] to ambient air quality in a nearby area that does not meet [the NAAQS].” 42 U.S.C. § 7407(d) (emphasis added). We conclude, to the contrary, that the designations are consistent with the EPA’s reasonable interpretation of the ambiguous statutory term “nearby.”
The EPA, however, had taken a different approach in the 2008 Guidance, instead interpreting “nearby” as presumptively including counties in the same metropolitan area as the violating county. 2008 Guidance at 3. In the Guidance, the EPA acknowledged that certain regions have ozone transport problems, but it concluded that the Act “does not require that all contributing areas be designated nonattainment, only the nearby areas.” Id. at 4. The agency explained that “[Regional strategies, such as those employed in the Ozone Transport Region and EPA’s NOx SIP Call are needed to address the long-range transport component of ozone nonattainment.” Id. In keeping with this understanding of the statute, the EPA declined to designate “super-regional” nonattainment areas, see Responses to Significant Comments on the State and Tribal Designation Recommendations for the 2008 Ozone NAAQS at 8-9 (Apr. 30, 2012) [hereinafter Response to Comments], and instead made more limited nonattainment designations in both Delaware and Connecticut, see Delaware Area Designations for the 2008 Ozone NAAQS 2; Connecticut Area Designations for the 2008 Ozone NAAQS 1.
We evaluate the EPA’s interpretation of a Clean Air Act provision under the familiar two-step Chevron framework. See Util. Air Regulatory Grp. v. EPA — U.S. -, 134 S.Ct. 2427, 2439, 189 L.Ed.2d 372 (2014) (citing Chevron, U.S.A., Inc. v. Natural Res. Def. Council, Inc., 467 U.S. 837, 842-43, 104 S.Ct. 2778, 81 L.Ed.2d 694 (1984)). The first question— “whether Congress has directly spoken to the precise question at issue,” Chevron, 467 U.S. at 842, 104 S.Ct. 2778 — has previously been resolved by this Court. In Pennsylvania Department of Environmental Protection v. EPA (PADEP), we held that the statutory term “nearby” in section 107(d) is ambiguous; indeed, we reached that conclusion in the course of addressing the precise argument that Delaware makes here. See 429 F.3d 1125, 1129-30 (D.C.Cir.2005). In Catawba County, we reached the same conclusion. See 571 F.3d at 35 (noting that section 107(d) does not define “nearby,” and that it is “the kind[ ] of word[ ] that suggests] a congressional intent to leave unanswered questions to an agency’s discretion and expertise”).
Recognizing these precedents, Delaware and Connecticut conceded at oral argument that our analysis must be governed by Chevron’s second step, Oral Arg. Recording at 3:49-3:54, which requires us to ask only whether the EPA’s interpretation is reasonable, see, e.g., PADEP, 429 F.3d at 1130. But we have addressed that question once as well, also in PADEP, where we said that “Chevron requires that we defer to the agency’s reasonable interpretation of the term, and Delaware has given us no reason to think that EPA’s interpretation is unreasonable.” Id. We reach the same conclusion here.
Second, the EPA’s construction is consistent with the approach the agency has taken in prior designations proceedings— an approach that this Court has previously upheld as reasonable. See PADEP, 429 F.3d at 1127, 1129-30; 2008 Guidance at 3.
Third, the EPA’s construction is consistent with the statutory scheme. The EPA selected the metropolitan area as the presumptive “nearby” area for its contribution analysis in part because the Congress itself chose the metropolitan area as the default boundary for ozone nonattainment areas classified as “serious,” “severe,” or “extreme.” See 42 U.S.C. § 7407(d)(4)(A)(iv); 2008 Guidance at 3 n. 5. The Congress’ choice is certainly evidence that the legislature envisioned broad but relatively local nonattainment areas.
As in PADEP, the petitioners argue that the EPA’s interpretation is unreasonable because it fails to appreciate the role of ozone transport, and consequently yields designations that fail to include the true contributors to their nonattainment status. See PADEP, 429 F.3d at 1129-30. Delaware notes, for example, that 84 to 94 per cent of its ozone results from the contributions of other states, including states as far west as Missouri. See Delaware Reply Br. 4. Without emissions reductions from those states, petitioners argue, they cannot meet the 0.075 ppm standard. Thus, by failing to address the principal sources of their ozone pollution, the EPA’s interpretation eliminates any possibility that they will attain the NAAQS.
Although we are sympathetic to the petitioners’ concerns, our role is not to decide whether their proposed interpretation is reasonable. Instead, the sole question before us is whether the EPA interpreted the term reasonably and consistently with the statute. See PADEP, 429 F.3d at 1130 (noting that, although a broader “construction of ‘nearby’ may well be sensible, Chevron requires that we defer to the agency’s reasonable interpretation of the term”). Here, the EPA had already considered the problem the petitioners raised. Part of the rationale for using the metropolitan area as the starting point for the contribution analysis was to account for ozone transported from outside the violating county. See 2008 Guidance at 3-4. Although this approach does not fully account for longer-range, interstate transport, the EPA has addressed that problem in regulations promulgated under other provisions of the Act. See, e.g., Federal Implementation Plans: Interstate Transport of Fine Particulate Matter and Ozone
The petitioners note that our decision in PADEP rested in part upon the fact that there, Delaware had “offered no evidence that ‘in practice’ EPA will not enlarge a nonattainment area in response to [its then] eleven-factor analysis,” 429 F.3d at 1130. Indeed, in PADEP, Delaware had failed altogether “to produce an eleven-factor analysis.” Id. But we did not mean by this to suggest that, had Delaware produced the appropriate factor analysis, the EPA would have been required to adopt an interpretation of “nearby” that included states as far away as those within the petitioners’ proposed nonattainment areas. The points discussed above — including the dictionary definition of “nearby” and the consistency of the EPA’s interpretation with the statute and its prior practice— strongly suggest that the EPA’s narrower interpretation would still be reasonable.
Nonetheless, if the petitioners had submitted a persuasive five-factor analysis establishing contributions from farther-away states, that would be relevant to our assessment of the reasonableness of the EPA’s refusal to enlarge the nonattainment area beyond its presumptive scope. In this case, however, although the petitioning States did submit technical analyses, they failed to demonstrate the requisite linkages under the EPA’s 2008 Guidance. See, e.g., Delaware Response Attach. 2 at 5-7, 11-13 (disputing relevance of factors related to urbanization, traffic, and economic growth); id. at 14-15 (with respect to meteorology factor, describing long-range transport without describing weather patterns within the proposed 16-state nonattainment area). Hence, the petitioners did not show that the agency “will not enlarge a nonattainment area in response to” the (current) five-factor analysis, PADEP, 429 F.3d at 1130. Rather, the States’ analyses were simply insufficient to overcome the agency’s definitional presumption.
In sum, we conclude that the EPA’s final designations of Delaware and Connecticut counties are consistent with a reasonable interpretation of the Clean Air Act.
Petitioner WildEarth Guardians (Wild-Earth) challenges the EPA’s designation of Uinta Basin, Utah, as “unclassifiable.” We find the EPA’s designation rational and in accordance with the Clean Air Act, and we therefore deny WildEarth’s petition.
1. Uinta Basin Background
The EPA requires every state to establish a network of regulatory monitoring stations to collect ozone air-quality data. See 40 C.F.R. pt. 58. The number of regulatory monitors required in an area depends, in part, on the area’s population. See id app. D. tbl.D-2. Areas with populations below 50,000 and many areas with fewer than 850,000 inhabitants require no regulatory monitors. Id Many rural areas therefore lack monitors.
Uinta Basin, Utah, had no regulatory monitoring until April 2011. The pre-2011 absence of regulatory-air-quality monitors in Uinta Basin meant that, when the EPA in 2013 conducted the designation process for the 2008 NAAQS, the agency had regulatory data for Uinta Basin for only two years — 2011 and 2012. The 2008 ozone NAAQS, however, reflect three-year averages of ozone levels. See 2008 Designations Rule, 77 Fed.Reg. at 30,089. Noting that “there are not yet three consecutive years of certified ozone monitoring data available [from Uinta Basin] that can be used to determine the area’s attainment status,” id, the EPA designated the area as “unclassifiable,” which the Clean Air Act defines as an area that “cannot be classified on the basis of available information as meeting or not meeting” the NAAQS, 42 U.S.C. § 7407(d)(1)(A)(iii).
Although no regulatory data exist for Uinta Basin prior to 2011, private companies working under consent decrees have been required to operate ozone air-quality monitors in Uinta Basin since 2009. See Letter from Robin Cooley, Counsel, Wild-Earth Guardians to Lisa P. Jackson, Adm’r, EPA 3 (July 19, 2012). Under the terms of those consent decrees, the private monitors must comply with many of the same requirements as regulatory monitors. See Consent Decree ¶¶ 80-81, United States v. Kerr-McGee Corp., No. 1:07-cv-01034 (D. Colo. May 17, 2007). From 2009 to 2011, the private monitors provided raw data showing ozone levels significantly exceeding the 2008 ozone NAAQS. The EPA found the 2009 to 2011 private data insufficient to support a nonattainment designation.
2. The Private Monitoring Data Challenge
WildEarth argues that, in light of the private data, the EPA contravened the Act’s requirements when it designated Uinta Basin as unclassifiable rather than nonattainment. We disagree.
The Act calls for the EPA to make designations “on the basis of available information.” 42 U.S.C. § 7407(d)(1)(iii). We have repeatedly found similar language to be ambiguous when assessing whether to defer to an agency’s construction. See Catawba Cnty., 571 F.3d at 35, 38 (finding the phrase “based on air quality monitoring data” to be ambiguous); Sierra Club v. EPA, 356 F.3d 296, 305-06 (D.C.Cir.2004) (finding the phrase “based on photochemical grid modeling” to be ambiguous). The EPA therefore may interpret the statutory language as it sees fit, as long as its interpretation is reasonable. Chevron, 467 U.S. at 845, 104 S.Ct. 2778. And even assuming the Act obligates the EPA to consider certain types of data, there would be no obligation for the agency to base its designations on data it reasonably considers to be unsound, at least if it “adequately explain[s] its reasons for rejecting ... data” on which it declines to
The EPA reasonably explained that the private monitoring data afforded an insufficient basis for a nonattainment designation because the agency was unable to perform post-collection quality assurance checks on the data. In particular, the EPA lacked quality assurance data needed to verify and audit the private data. As the agency explained:
Quality assurance data consist, primarily, of biweekly single point quality control (QC) checks, used to assess the precision and bias a given instrument is displaying in its day-to-day measurements, and annual independent performance evaluations (audits) of equipment, which rely on independent staff and measuring systems to confirm that the monitors are operating as expected and required.
Letter from Lisa P. Jackson, Adm’r, EPA to Robin Cooley, Counsel, WildEarth Guardians 5 (Dec. 14, 2012) (denying reconsideration of Uinta Basin designation). The agency determined that, without audits or quality control checks, it could not adequately verify the quality of the private data. That explanation comports with common sense and falls within the substantial deference accorded the EPA in evaluating the soundness of data available to it.
WildEarth presses several counterarguments, none of which we find persuasive. First, WildEarth observes that the consent decrees required the private monitors to operate in “substantial compliance” with 40 C.F.R. Part 58, the quality assurance requirements under which regulatory monitors operate. But “substantial compliance” is not “full compliance,” and the EPA could reasonably draw a distinction between the two. Moreover, data from regulatory monitors — which must be collected in compliance with 40 C.F.R. Part 58 — undergo post-collection auditing and verification processes. See, e.g., 40 C.F.R. pt. 58, app. A, § 3. Those post-collection processes could not be conducted for the private monitor data. Accepting Wild-Earth’s argument would require us to conclude that the EPA must apply less stringent post-collection validation requirements to data collected from private monitors in “substantial compliance” with the agency’s data-collection regulations than the agency applies to data collected from regulatory monitors in actual compliance with those regulations. We see no reason to embrace that counterintuitive result.
Second, WildEarth points out that the EPA has encouraged other federal entities to take notice of the private monitoring data. The EPA acknowledges that it argued, in a judicial proceeding supporting entry of the same consent decrees mandating the private monitoring, that the private monitors would provide data that would be “rehable and of good quality” and “useful in assisting regulators.” Resp’t’s Br. 57. And indeed the data have proven helpful to the EPA in other regulatory contexts. On the basis of the private data, for example, the EPA informed the Forest Service that Uinta Basin ozone concentrations “exceed the NAAQS” and are a “serious problem.” Supp. JA 387.
We agree with WildEarth that an agency may be required to articulate why data are sufficiently rehable for one purpose but not for another. See Cnty. of L.A. v. Shalala, 192 F.3d 1005, 1022 (D.C.Cir.1999). But the EPA has done so here. That the data may be sufficiently reliable to warrant identifying ozone as a serious issue for a Forest Service analysis under
That the EPA partially relied on the private data in the course of this very designation process does not undercut that conclusion. While “unclassifiable” represents a single statutory designation, see 42 U.S.C. § 7407(d)(1)(A)(i)-(iii), the EPA further divided that classification into two sub-categories: “unclassifiable/attainment” and “unclassifiable.” See 2008 Designations Rule, 77 Fed.Reg. at 30,089. “Historically for ozone,” the EPA designates as “ ‘unclassifiable/attainment’ ” those areas for which “air quality information is not available because the areas are not monitored.” Id. at 30,090. But in Uinta Basin, the EPA instead designated the area “unclassifiable” after determining that the private monitoring “detected levels of ozone that exceed the NAAQS.” Id. at 30,089.
There is no arbitrariness in the EPA’s choice partially — but not fully — to rely on the private data. At the outset, we note that the parties point us to no material differences between an “unclassifiable/attainment” and an “unclassifiable” designation, and we are aware of none. See 40 C.F.R. § 51.1100(g) (“Attainment area means, unless otherwise indicated, an area designated as either attainment, unclassifiable, or attainmeni/unclassifiable.”); cf. 42 U.S.C. § 7471 (instructing the EPA to give the same treatment to “unclassifiable” and “attainment” areas for SIP purposes). But given the EPA’s decision to create two different unclassifiable designations, we will assume arguendo that materially different regulatory burdens attend each designation. Even then, however, we agree with the EPA that it was reas